This invention relates to improvements in a top coat for an outer panel of an automotive vehicle, a coating method for the top coat, and a coat film formed by the coating method, and particularly to the top coat which is excellent in staining resistance, water repellency, oil repellency, acid rain resistance, scratch resistance and the like, the coating method for the top coat, and the coat film formed by the coating method.
In a top coat for an outer panel of an automotive vehicle, melamine cross-linking has been generally used to harden the coat film of the top coat. However, the melamine cross-linking has such a disadvantage as to be low in acid rain resistance. In order to overcome this disadvantage, a non-melamine type top coat using acid-epoxy cross-linking has been developed for the outer panel of the automotive vehicle. Further, in order to add the staining resistance to the top coat using the acid-epoxy cross-linking, blending a fluororesin or the like has been tried as disclosed in Japanese Patent Provisional Publication No. 11-323242.